• Environmental and Resource Economics Review
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• v.18 no.1
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• pp.105-138
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• 2009

This study investigates the spatial distribution of the degree of water pollutants in Han River using data obtained by the water pollution observation stations. This study estimates a non -parametric kernel density function for each water pollutants, and tests a significant difference between two estimated distribution functions. Next, Generalized Entropy inequality indices are evaluated and this research tests difference of inequality indices between two years using bootstrapping method. Lastly in a dynamic of view, it is analyzed that there are significant changes in the ranking of water pollution level. Estimation results show that the degree of inequality in spatial distribution of water pollution tends to be stable or decreasing for last 15 years in a great part of water pollutants, and ranking of water pollution level hardly changes in Han River.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1444-1445
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• 2008

최근 Wireless Local Area Network(WLAN), Wide-band Code Division Multiple Access(WCDMA), CDMA2000, Bluetooth 등 다양한 모바일 통신 시스템에 대한 수요가 증가하고 있다. 이와 같은 모바일 통신 시스템에는 70dB이상의 SFDR(Spurious Free Dynamic Range)을 가진 ADC(Analog-to-Digital Converter)가 사용된다. 본 논문에서는 모바일 통신 시스템을 위한 SFDR 70dBc의 성능을 제공하는 10비트, 100Msps 파이프라인 ADC를 제안한다. 제안한 ADC는 요구되는 해상도 및 속도 사양을 만족시키기 위해 3단 파이프라인 구조를 채택하였으며, 입력단 SHA(Sample and Hold)회로에는 Nyquist 입력에서도 10비트 이상의 정확도로 신호를 샘플링하기 위해 부트스트래핑 기법 기반의 샘플링 스위치를 적용하였다. residue amplifier 회로에는 전력을 줄이기 위해 8배 residue amplifier 대신 3개의 2배 ressidue amplifier를 사용하였다. ADC의 높은 사양을 만족시키기 위해서는 높은 이득을 가지는 op-amp가 필수적이다. 제안한 ADC 는 0.18um CMOS 공정으로 설계되었으며, 100Msps의 동작 속도에서 70dBc 수준의 SFDR과 60dB 수준의 SNDR(Signal to Noise and Distortion Ratio)을 보여준다.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.41-50
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• 2021

This paper analyzes the efficiency of social enterprises by analyzing bootstrapping data envelopment analysis. Unlike the definitive DEA model, we analyze the confidence intervals of efficiency estimates through the DEA model, which takes into account stochastic factors. Major analysis results are summarized as follows: First, the results of the bootstrapping DEA analysis of social enterprises estimated that the technical efficiency was 0.459 and the 95% confidence interval was 0.389 to 0.601. Second, the number of inefficient social enterprises with efficiency values of less than 0.5 was found to be 15 (55.56%) in technical efficiency, 5 (18.52%) in pure technical efficiency, and 8 (29.63%) in scale efficiency. It can be seen that a significant number of social enterprises are operating in an inefficient state. Third, looking at the returns of scale of social enterprises, 25 (67.57%) are currently in the increasing returns of scale, 10 (27.02%) are in the constant returns of scale, and 2 (5.41%) are in decreasing returns of scale. In other words, it can be seen that social enterprises are under-invested in terms of input factors.

• 한국벤처창업학회:학술대회논문집
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• 2023.11a
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• pp.139-143
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• 2023

최근 교사들의 잇단 극단적 선택으로 학교의 변화와 상황에 대한 문제의식이 사회적으로 날로 높아지고 있다. 교직에 대한 선호도가 급격히 떨어지고 교직 이직 비율도 빠르게 높아지고 있어 교육의 질을 걱정하기에 이르렀다. 드러난 문제가 원인의 하나일 수 있으나 많은 연구에서 교사들의 직무스트레스가 심각한 수준임을 밝히고 있고, 학교교육 현장에는 교사들이 조직에 몰입하기 어려운 다양한 문제들이 있음을 밝히고 있다. 그럼에도 교육현장에서는 학생, 교사들이 함께 성장할 수 있고 모두가 만족하는 교육 활동을 실현시키고 변화와 혁신을 통해 교육역량을 높이고자 지속적으로 노력하고 있다. 본 연구는 초등학교 교사의 직무스트레스와 감정 노동이 조직몰입에 미치는 영향을 조사 분석하고 두 변인 즉 직무스트레스와 감정 노동이 직무몰입에 미치는 영향에서 긍정심리자본의 매개 효과를 알아보는데 그 목적이 있다. 교사 직무스트레스 실태를 종합적으로 파악하고자 관계 요인, 업무요인, 정책 요인으로 나누어 분석(김종민 외, 2018. 경기도교육연구원)하고 특히 스트레스 요인 중 가장 비중 있는 감정 노동 부분은 분리하여 더 상세히 분석하고자 한다. 이를 위해 경기도, 경기도, 서울, 전라남도 소재 초등학교교사 500명을 대상으로 자료를 수집하여 SPSS 20.0 프로그램을 활용하여 변인들의 기술통계치를 산출하고자 한다. 초등교사의 인구통계학적 변인간에 유의한 차이가 있는지 확인하기 위해 t-검정과 일원배치 분산분석(ANOVA)을 실시한다. 그리고 연구에 포함된 변인들간의 상관계수를 산출하고 Baron과 Kenny(1986)의 절차에 따른 3단계 회귀분석과 부트스트래핑(bootstrapping) 기법을 적용하여 매개효과의 유의성을 검증하고자한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.227-236
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• 2016

This study tested the effects of stress on smartphone addiction via depression and self-efficacy among college students, and the analysis results were as follows: setting mediator and extra variables significantly correlated with the criterion variable as covariates and applying the regression analysis and SPSS Macro as well as bootstrapping method, to verify the mediating effects of depression and self-efficacy in stress and smartphone addiction. This study analyzed the direct effects of stress on the depression, self-efficacy, and smartphone addiction of college students and found that stress had direct effects on their depression and self-efficacy and also indirect effects on their smartphone addiction via depression and self-efficacy. Both depression and self-efficacy had dual and partial mediating effects on the influences of stress on their smartphone addiction. Stress had significant dual mediating effects on their smartphone addiction via the indirect paths of depression and self-efficacy, and high stress also had significant direct effects on their smartphone addiction, thus validating the dual mediation model. These findings demonstrate the need to develop programs to mitigate the stress and depression of college students and enhance their self-efficacy in order to reduce their smartphone addiction.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.440-452
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• 2019

The objective of this study is to analyze the mediation effect of communication and interpersonal relations in the impact of job stress of female workers with disabilities on organizational commitment. The subjects are 508 female workers with disabilities who participated in the 1st wave of the Panel Survey of Employment for the Disabled in Years7-8 (2014-2015). A multiple regression analysis was conducted, and the mediation effect was verified according to the research procedures of Baron and Kenny(1986) using bootstrapping. The results showed that organizational justice and work environment stress faced by female workers with disabilities had a negative impact on organizational commitment, and communication and interpersonal relations had a partial mediation effect. Based on these results, this study suggested ways to reduce job stress and increase organizational commitment of female workers with disabilities.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.181-186
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• 2022

This study examines the effect of parenting stress on children's social competence in relation to parenting stress, children's social competence, and parents' self-esteem, The purpose of this study is to investigate whether parental self-esteem mediates the relationship between parenting stress and children's social competence. Frequency analysis and descriptive statistical analysis were performed on the data of the 7th year of 2014 Panel Study of Korean Children(PSKC), and Pearson's moment correlation coefficient was calculated for correlation analysis between variables. In addition, in order to verify the mediating effect of parental self-esteem in the relationship between parenting stress and the child's social competence, Process Macro Model 4 was applied to verify the mediating effect, The significance of the indirect effect was verified by the bootstrapping method. As a result of this study, first, the correlations between all latent variables showed significant correlations. Second, it was confirmed that mother and father self-esteem had a mediating effect in the effect of father and mother's stress on infants' social competence. These results suggest that in order to improve children's social competence, parents should be able to increase their self-esteem so that they can have faith and confidence in themselves and control their emotions well in parenting stressful situations.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.201-208
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• 2023

This study is a empirical study to investigate the mediating effect of self-efficacy and social support in the relationship between SNS use time and acculturation stress for Chinese students. A survey was conducted from April 1 to 12, 2022 on 239 Chinese students from universities across the country using Wenjuanxing questionnaires. Descriptive statistics analysis and Baron and Kenny hierarchical regression analysis were performed on the collected data using SPSS 26.0, and bootstrapping was performed to verify the mediating effect. As a result of the study, SNS use time had a significant effect on the self-efficacy and social support. The acculturation stress was significantly influenced by SNS use time, self-efficacy, and social support. SNS use time had a significant effect on acculturation stress, and self-efficacy and social support had a partial mediating effect in the relationship between SNS use time and acculturation stress. Therefore, based on the above research, SNS can be used to develop the projects for International students to enhance their cultural adaptative ability and thus alleviate the acculturation stress. This study can serve as the foundational and supplementary materials for the follow-up study of SNS and acculturation stress.

• Korean Journal of Social Welfare
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• v.67 no.1
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• pp.239-261
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• 2015

This study investigated the impact of social capital on married immigrant women's parenting, specifically focusing on the mediating effect of parenting participation. Using structural equation modeling, social capital within and outside of the family were examined in their relations to parenting efficacy, and the mediating effect of parenting participation was analysed. Study participants were 459 immigrant women from the Gyeonggi Education Welfare Panel(2011), who had children in 5th and 6th grades of elementary school. Findings suggested that social capital within and outside of the family had significant impact on parenting participation, which in turn affected parenting efficacy. Direct effects of social capital on parenting efficacy were not statistically significant, indicating a full mediation effect of parenting participation. Implications for social work practice and social policy for this population are discussed.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1033-1043
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• 2011

In this paper, we use a nested family of models of Generalized Autoregressive Conditional Heteroscedasticity(GARCH) to verify asymmetric conditional heteroscedasticity in the KOSPI and Won-Dollar exchange rate. This study starts from an investigation of whether time series data have asymmetric features not explained by standard GARCH models. First, we use kernel density plot to show the non-normality and asymmetry in data as well as to capture asymmetric conditional heteroscedasticity. Later, we use three representative asymmetric heteroscedastic models, EGARCH(Exponential Garch), GJR-GARCH(Glosten, Jagannathan and Runkle), APARCH(Asymmetric Power Arch) that are improved from standard GARCH models to give a better explanation of asymmetry. Thereby we highlight the fact that volatility tends to respond asymmetrically according to positive and/or negative values of past changes referred to as the leverage effect. Furthermore, it is verified that how the direction of asymmetry is different depending on characteristics of time series data. For the KOSPI and Korean won-US dollar exchange rate, asymmetric heteroscedastic model analysis successfully reveal the leverage effect. We obtained predictive values of conditional volatility and its prediction standard errors by using moving block bootstrap.